Question

calculate the no of electrons flowing through the cross section of conductor when current of 20 ma flows for 50 seconds​

Answer 1

Explanation:

Answer :-

6.25 × 10¹⁸ electrons are flowing through the cross section of the conductor .

Explanation :-

We have :-

→ Current (I) = 20 mA

→ Time taken (t) = 50 seconds

→ Charge of an electron (e) = 1.6 × 10⁻¹⁹ C

To find :-

→ Number of electrons (n) .

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Firstly, let's convert the given unit of current from mA to A .

⇒ 1 mA = 0.001 A

⇒ 20 mA = 20(0.001)

⇒ 0.02 A

Now, we know that :-

I = Q/t

⇒ I = ne/t

⇒ 0.02 = (n × 1.6 × 10⁻¹⁹)/50

⇒ 0.02(50) = 1.6 × 10⁻¹⁹ n

⇒ 1 = 1.6 × 10⁻¹⁹ n

⇒ n = 1/(1.6 × 10⁻¹⁹)

⇒ n = 1/1.6 × 1/10⁻¹⁹

⇒ n = 0.625 × 10¹⁹

⇒ n = 6.25 × 10¹⁸

Answer 2

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6.25 × 10¹⁸ electrons are flowing through the cross section of the conductor .

Explanation :-

We have :-

→ Current (I) = 20 mA

→ Time taken (t) = 50 seconds

→ Charge of an electron (e) = 1.6 × 10⁻¹⁹ C

To find :-

→ Number of electrons (n) .

________________________________

Firstly, let's convert the given unit of current from mA to A .

⇒ 1 mA = 0.001 A

⇒ 20 mA = 20(0.001)

⇒ 0.02 A

Now, we know that :-

I = Q/t

⇒ I = ne/t

⇒ 0.02 = (n × 1.6 × 10⁻¹⁹)/50

⇒ 0.02(50) = 1.6 × 10⁻¹⁹ n

⇒ 1 = 1.6 × 10⁻¹⁹ n

⇒ n = 1/(1.6 × 10⁻¹⁹)

⇒ n = 1/1.6 × 1/10⁻¹⁹

⇒ n = 0.625 × 10¹⁹

⇒ n = 6.25 × 10¹⁸